The purpose of hallucinations is to replace real signals with simulated sensory signals that drive the autonomic nerves to perform psychosomatic actions. The patient has a dreamlike sensation, as if in a dream, often in conjunction with hallucinations, which are proven to be illusory by objective tests due to the lack of corresponding realistic stimuli, but are not illusory in terms of the patient’s own experience. Some patients are convinced that their perceptions come from objective reality. What are the tests for hallucinations? 1.Laboratory tests: including complete blood count, blood glucose, liver function, kidney function, blood ammonia, blood gas analysis, urinalysis, urine drug screening. 2, Do serial EEGS tracing: Observe that delirium is seen with substantial changes in EEGs. Structural disruption and general slowing of brain wave rhythms are the most common alterations. The degree of rhythm slowing correlates with the degree of hallucinations. 3, intracranial etiology: other EEG changes can be seen that cause hallucinations, including focal slow waves, asymmetric δ activity and paroxysmal emission (spike, sharp wave, spike-slow wave synthesis). Periodic integrated waves such as triphasic waves and periodic lateral epileptiform emission can help in the diagnosis of delirium caused by focal brain injury such as liver failure and cerebral hemorrhage. 4, other auxiliary: tests include chest X-ray, ECG, CT, MRI, etc. Hallucination is a subjective experience where the subject’s feelings are similar to perception. It is a more serious perceptual disorder. Because its feelings are often realistic and vivid, it can cause anger, sadness, panic, escape and even produce emotional or behavioral reactions to attack others.